遮罩

// 遮罩层
    .mask-view {
        width: 100%;
        height: 100%;
        background-color: rgba(0,0,0,0.5);
        z-index: 5;
        position: fixed;
        top: 0rpx;
        left: 0rpx;
    }

<view class="mask-view" v-if="dispose" ></view>

v-if="dispose"：用来判断遮罩是否显示，默认值给false

 background-color: rgba(0,0,0,0.5)：0.5是透明度